In the liquid chromatography, analytical columns are used for quantitative and/or qualitative analysis of sample components. In general, the analytical columns are housed in a column oven and adjusted to a constant temperature (see Patent Document 1). In method scouting for searching for an analytical column suitable for a sample or when a column manufacturer performs a quality inspection of analytical columns, a column oven capable of housing a plurality of analytical columns is used and the plurality of analytical columns are disposed in the column oven.
A flow path switching valve for switching between the analytical columns to be used is provided on an upstream side of the analytical columns in the column oven, and the flow path switching valve is switched to thereby select the analytical column to be used for the analysis.
Patent Document 1: Japanese Patent Laid-open Publication No. 2015-045532